After news earlier this week of the Curiosity rover petting and naming its new pet rock, Jake Matijevic, NASA released images today indicating that long ago, water probably flowed on the Martian surface.

Other notable images recently sent back from Mars include one from Curiosity’s older, but smaller rover sibling, Opportunity, that photographed small spherical objects, nicknamed “blueberries,” with it’s Microscopic Imager providing important evidence about long-ago wet environmental conditions.